There's a finite number of ranges someone can attack from, you don't have to be throwing actions out to utilize samus' zoning.
Where is your opponent camping you? Are they horizontal on the other side of the stage? Walk forward until they can't safely act because of the threat of ftilt/jab/cc etc
"But what if they use their speed to avoid me when I walk up???"
Well where can they go? To the ledge? That's bad, hold your position and punish their ledge or return to stage option. To the platform? Also bad, zone them out using fair. What about dj? Trickier, but cover the landing if you can (fair is good hear too, it has a considerable disjoint).
Well, what about a dj to top plat? You could try a fair or uair here but samus has a hard time getting up there--- at this point you pull out your samus fundamentals and cover your opponents descent when they choose to leave the top plat (there's a finite number of places they're going to go after going to top plat). If you're on yoshis/fod you could cover with upb here as well if they're conditioned or you catch them napping.
"But what if they hit me out of my approach???"
What are they hitting you with? Is it cc-able? Bait them to attack you and punish. Are they out of range of your cc->attack? They have to commit to that kind of spacing; read and punish it. Is it a crossup? They have to move thru you for that. Upb or disengage to neutral.
Most importantly where are they hitting you. Are they dropping from side plats? Dropping thru plats? Shffling out of neutral? Dropping from the top plat?
I like to make a map of 'no go zones' in my head; areas I know my opponent likes to attack from. By just choosing to not be in those areas you're probably taking away your opponents strongest approach; this is frustrating for them, so capitalize. You can also bait it out by faking encroachment on those areas.
TLDR/FINAL THOUGHTS
The main point here is that even if you're not throwing out hitboxes or wavedashing up a storm you can still manipulate your opponents options thru spacing. When you move forward what do they do? Attack? Jump up? Run away? All of those infer what kind of option they can choose next and what kind of option you can punish with. At the most basic level, move forward, read their response and punish. At higher levels you'll have to do a movement->read/react at their movement->do another movement that diminishes their options->read/react at their movement->etc. Play out that interaction til they have no more options and then punish.